• Carbon dioxide enrichment;
  • Digitalis lanata;
  • digoxin;
  • greenhouse cultivation;
  • greenhouse water cooling


A versatile method was developed for the application of 1000 ppm CO2 during the whole growth period of plants. Temperature controlled water cooling and ventilation of the greenhouse resulted in a monthly CO2 enrichment time of 60 to 90 % of the total light period. Digitalis lanata, grown in greenhouses with CO2 enrichment during the whole growth phase from April to November, produced twice as much biomass as field cultivated plants.

The relative yield of the glycoside digoxin per gram Digitalis drug dry weight was 0.4% in field grown and 0.7% in greenhouse cultivated plants. The production of digoxin per hectare in the greenhouse at 1000 ppm CO2 was almost 3.5-fold that by field cultivation. Drug yield and secondary metabolite production in D. lanata were remarkably influenced by increased temperature and elevated CO2 partial pressure in the greenhouse.